首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   235187篇
  免费   48683篇
  国内免费   1310篇
耳鼻咽喉   3542篇
儿科学   7061篇
妇产科学   4404篇
基础医学   38898篇
口腔科学   8056篇
临床医学   27044篇
内科学   52557篇
皮肤病学   11381篇
神经病学   24666篇
特种医学   10363篇
外科学   34772篇
综合类   2285篇
现状与发展   5篇
一般理论   101篇
预防医学   13820篇
眼科学   5533篇
药学   18936篇
中国医学   2413篇
肿瘤学   19343篇
  2023年   1022篇
  2022年   2799篇
  2021年   6072篇
  2020年   7193篇
  2019年   13655篇
  2018年   13854篇
  2017年   13841篇
  2016年   15355篇
  2015年   16711篇
  2014年   17937篇
  2013年   19901篇
  2012年   16579篇
  2011年   16148篇
  2010年   15560篇
  2009年   11046篇
  2008年   11263篇
  2007年   10073篇
  2006年   9350篇
  2005年   8769篇
  2004年   7909篇
  2003年   6945篇
  2002年   6209篇
  2001年   5240篇
  2000年   4797篇
  1999年   3622篇
  1998年   1381篇
  1997年   1044篇
  1996年   996篇
  1995年   909篇
  1994年   783篇
  1993年   676篇
  1992年   1659篇
  1991年   1654篇
  1990年   1405篇
  1989年   1295篇
  1988年   1211篇
  1987年   1079篇
  1986年   1053篇
  1985年   935篇
  1984年   687篇
  1983年   595篇
  1982年   425篇
  1981年   393篇
  1980年   355篇
  1979年   535篇
  1978年   426篇
  1977年   401篇
  1976年   351篇
  1974年   371篇
  1973年   341篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
Background/aims: The objective and quantitative assessment of the skin is important in medical and cosmeceutical research. Assessment of color is an important element for analyzing the surface of the skin, which is usually determined subjectively by a doctor or using color analysis devices. These devices, however, cannot provide correct color information because color is construed from the mean value of the observation region, and analysis of color distribution is impossible. The purpose of this paper is to develop an objective analysis method to permit skin color measurement of each pixel unit of an image and analyze the distribution of skin surface color. Methods: The Skin Color Distribution Analyzer (SCDA) is an analysis method newly developed at the Research Institute for Skin Image at Korea University. The SCDA system presented in this paper performed a novel form of quantitative and objective analysis of skin color distribution using each pixel color model parameter found in image wavelength information. In this paper, distribution analysis was conducted on normal skin and skin lesions and skin affected by artificially induced irritant contact dermatitis and pigmented nevous. The method selected a grade using a color model parameter. Twenty healthy Korean males participated in this study. A comparative study of the eight anatomical areas was performed, including the exposure and non‐exposure parts and the medial aspect and the lateral aspect of the forearm. A reliability test for the SCDA system was also conducted with a spectrometer (SPEC) using the color analysis method. Results: Each skin lesion was precisely segmented by grade and each parameter hada different statistical significance for results of analysis of distribution in pigmented nevous and the artificially induced irritant contact dermatitis. Parameters L*, b*, a*, and EI showed salient traits. Showed resemble measured result in the SCDA system and the SPEC of normal skin. The exposed site, in comparison with the non‐exposed site, showed a notable difference in the L* parameter and a significant statistical difference in the x and z parameters, except b*. The comparison of the medial and lateral aspects of the forearm showed a notable difference in the L* parameter and a significant statistical difference in the parameters except y and b*. In the reliability test result using the SCDA system and the SPEC, the SCDA system was highly reliabile in terms of the CV value in all color model parameters. Conclusions: The color distribution analysis method using the SCDA system has revealed an aspect that the existent method of medical research has not shown, and is considered to be more reliable than other methods. This method can provide better study findings because it can be applied to other fields in addition to the medical science field and the ripple effect is thought to be bigger in other science field too.  相似文献   
55.
Ganoderma sinensis has been used widely in Oriental countries for the prevention and treatment of various diseases including cancer. Previous studies have shown that the lipid extract from Ganoderma exhibits direct cytotoxicity against tumor cells. Here, it is reported that the lipid extract from germinating G. sinensis spores, at lower concentrations that have no direct tumoricidal activity, induce potent antitumor immune responses in human monocytes/macrophages. Upon stimulation with the lipid extract, monocytes/macrophages exhibited markedly increased production of proinflammatory cytokines and surface expression of costimulatory molecules. Conditioned medium from stimulated cells effectively suppressed the growth of tumor cells. Apparently, the lipid extract triggered macrophage activation via a mechanism different from that associated with LPS. Moreover, it was observed that the lipid extract could partially re‐establish the antitumor activity of the immunosuppressive tumor‐associated macrophages. These results indicated that in addition to its direct tumoricidal activity, the lipid extract from G. sinensis spores could exert antitumor activity by stimulating the activation of human monocytes/macrophages. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
56.
57.
58.
59.
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号